Sol-Gel Synthesis of Single Phase, High Quantum Efficiency LiCaPO4:Eu2+Phosphors

This paper reports the synthesis and luminescence properties of blue emitting Li(Ca 1−x Eu x )PO 4 (x = 0.005, 0.01, 0.03) phosphors. These phosphors were prepared by a modified sol-gel/Pechini method. The particle size ranged from 1 to 1.5 μm with a narrow size distribution. X-ray diffraction analysis shows that the phases present are dependent on the post-synthesis annealing temperature and x. A single phase of this phosphor is obtained at x ≤ 0.01 and an annealing temperature of 800°C. These phosphors are excited efficiently in the range 280-410 nm and the photoluminescence emission spectra consist of a strong broad blue band centered at ∼470 nm. Furthermore, the quantum efficiencies range from 58% to 73% depending on the annealing conditions.